Motor imagery is suggested to be functionally equivalent to physical execution as they each utilise a common neural representation. The present study examined whether motor imagery correspondingly reflects the spatial characteristics of physically executed movements, including the signal-dependent noise that typically manifests in more variable end locations (as indicated by effective target width; W_e). Participants executed or imagined a single, upper-limb target-directed aim in the horizontal medio-lateral direction. The start and end of the imagined movements were indexed by the lifting and lowering of the limb over the home position, respectively. Following each imagined movement, participants had to additionally estimate their imagined end location relative to the target. All the movements had to be completed at a pre-specified criterion time (400 ms, 600 ms, 800 ms). The results indicated that the W_e increased following a decrease in movement time for execution, but not imagery. Moreover, the total error of imagined movements was greater than the actual error of executed movements. While motor imagery may comprise a neural representation that also contributes to the execution of movements, it is unable to closely reflect the random sources of variability. This limitation of motor imagery may be attributed to the comparatively limited efferent motor signals.

运动图像被认为在功能上等同于物理执行，因为它们各自利用共同的神经表示。本研究检查了运动图像是否相应地反映了物理执行的运动的空间特征，包括通常在更多可变的终端位置（如有效目标宽度所表示； W _e）。参与者执行或想象了一个在上，中，下水平方向上的单一上目标定向目标。想象的运动的开始和结束分别通过肢体在原始位置上的升高和降低来进行索引。跟随每个想象的运动，参与者必须额外估计他们相对于目标的想象终点位置。所有运动必须在预先指定的标准时间（400 ms，600 ms，800 ms）完成。结果表明，W _e减少执行时间（而不是图像）会增加。此外，想象的动作的总误差大于执行的动作的实际误差。尽管运动图像可能包含神经表示，这也有助于运动的执行，但它无法紧密反映出随机性的可变性。运动图像的这种限制可以归因于相对有限的传出运动信号。